Spray 2 baking sheets with nonstick spray and set aside.
Combine the beef, sausage, breadcrumbs, Parmesan, milk, oregano, chile flakes, salt and pepper in a large bowl and mix well with your hands. Add the oil and egg and continue mixing with your hands until all the ingredients are combined. Use a small ice cream scoop to pop chunks out into your hand, then roll into meatballs. (This will ensure that the meatballs are all the same size.)
Place the meatballs on the prepared baking sheets and freeze for at least 2 hours and up to overnight.
Preheat the oven to 400 degrees F and line 2 baking sheets with nonstick parchment paper.
Lay out one of the sheets of puff pastry on a work surface, then use a knife to cut 18 thin strips, each strip measuring 1/2 inch wide by 9 inches long. Cut each strip in half crosswise. Repeat with the other sheet of puff pastry.
Wrap 2 strips of dough around each meatball like bandages, stretching the dough as necessary. Separate the "bandages" near one side of each to show the meatball "face." Place the meatballs on the lined baking sheets.
Bake until the pastry is golden brown and the meatballs are cooked through, 20 to 25 minutes. Let cool slightly. Put ketchup and mustard in squeeze bottles and use them to make little eyes. Serve.